Let them dry out completely, then use Table salt and Mayonnaise together in a paste and rub that in (Draws out the damp and feeds the wood). Ash and metal polish also work. Best wishes.
I've used this trick with an iron on wooden tables. https://www.exquisitelyunremarkable.com/2016/04/how-to-remove-water-stains-from-wood.html
Here's a post that might help = https://www.hunker.com/13415255/how-to-remove-dark-water-stains-from-hardwood-floors
Try restore a finish. Comes in various colors. It will remove white spots. If the spot is black, is has gotten into the wood. Then the piece needs to be removed and replaced.